Saint Helens Weather in September

The climate in Saint Helens during September can be summarized as mild and reasonably dry.

September is in the fall / autumn in Saint Helens and is typically the 4th warmest month of the year. Daytime maximum temperatures average around 17°C (63°F), whilst at night 10°C (50°F) is normal.

On average September is the 5th wettest month of the year in Saint Helens with around 76mm 3 inches of rain making it a reasonably dry time to visit. This rainfall is typically spread over 16 days, although this may vary considerably.

On the flip side this corresponds to an average of 4.5 hours of sunshine per day.

The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in Saint Helens in September 2025.